Biohacking: what the term means and what the evidence shows

2. März 2024 ca. 22 Minuten

Here’s what to expect in this article

1. Where the term comes from and what it means
2. Why no institution uses the term
3. Six practices and the evidence behind them
4. Intermittent fasting: what the DGE says
5. Caffeine in numbers: the upper limit
6. Cold exposure: what the sources actually say
7. Sleep: the best-studied lever
8. Dietary supplements and the stack concept
9. Wearables: what you measure and who can see it
10. What you can measure in your own body
11. Limitations: what this article doesn’t answer
12. What remains of biohacking
Frequently asked questions
Sources

Where the term comes from and what it means

Biohacking describes the attempt to deliberately influence your own body and observe the effects. The word comes from software, where a hack is a shortcut that bypasses the intended path. Applied to the body, it suggests control over a process that would otherwise simply run its course.

The term encompasses almost everything: intermittent fasting, cold showers, dietary supplements, sleep logs, light therapy lamps, rings, and watches with sensors. What these things have in common is not their effect, but the attitude behind them. You try something and measure what happens.

What’s new and what isn’t

Going to bed early, drinking less coffee in the evening, eating regularly: these aren't inventions of recent years. What's new is the measuring technology on your wrist and the language that turns it into a project.

This shift has a side effect that matters for this article. When an undisputed recommendation and an unsupported promise appear under the same term, both seem equally well-founded. But they are not, and the difference can be demonstrated.

Three meanings that get mixed up

In practice, the word refers to three quite different things. The first meaning is everyday optimization: sleep, diet, exercise, caffeine, all adjusted and monitored in small steps. This is the most harmless and, at the same time, the most common case.

The second meaning is self-tracking. Here, the focus is not on the intervention but on the numbers: sleep phases, resting heart rate, step count, recovery metrics. People measure what a sensor can provide and adjust what changes the graph.

The third meaning is the riskiest and the rarest in Germany. It includes interventions in the body using substances or implants, sometimes outside medical supervision. People talking about biohacking almost never mean this third level, yet the term encompasses it anyway.

This article is therefore subject to one limitation. It covers the first two levels, that is, what people actually do in everyday life. The third level is mentioned only where an institution explicitly warns against something.

Why no institution uses the term

For this article, we specifically looked to the organizations in Germany that assess health-related claims: IQWiG, DGE, BfR, RKI, the Federal Centre for Health Education, consumer advice centers, WHO, and the MSD Manual. None of these organizations uses the term biohacking in its own publications.

This is not proof that biohacking is harmful or ineffective. It simply means there is no vetted content behind the term. Only the individual components can be evaluated, and there are statements about those. One of them is representative of the situation.

This statement is revealing because intermittent fasting is the most frequently cited of all biohacking practices. If the evidence is described this way even for intermittent fasting, we can expect no more from less common methods.

Six practices and their evidence

The table compares the six most frequently mentioned practices. The middle column states what an institution actually says about them; the right-hand column shows what follows from that.

The third column stands out. None of the rows gives a clear yes or a clear no. Instead, they describe limitations, open questions, and side effects.

Intermittent fasting: what the DGE says

The DGE specialist information is cautious in its wording, and for good reason. In addition to the sentence quoted above, it notes that there are also no clinical studies comparing intermittent with periodic fasting.

The information is more explicit about the time horizon. According to this specialist information, there are no scientific studies on the long-term effects of intermittent fasting. So anyone wanting to use a method for years will find no data to go on.

Where many summaries go off track

The DGE cites animal studies suggesting that regular food abstinence may reduce the risk of type 2 diabetes, cardiovascular diseases, neurological diseases, and cancer. These findings come from animal studies, and that is exactly how they are presented.

This qualifier disappears in many retellings. A finding from an animal model becomes a claim about humans. The difference is not cosmetic: it determines whether a claim is supported by evidence or is a guess.

This source also leaves open how intermittent fasting affects mood, physical stamina, cognitive performance, and the risk of eating disorders. The last point deserves attention because rigid eating windows can become problematic for people with a predisposition.

Two forms that are often lumped together

In its specialist information, the DGE distinguishes between intermittent and periodic fasting. These refer to different rhythms: with one, eating and fasting periods alternate within a day or a week; with the other, longer fasting periods occur at greater intervals.

According to the same source, there are no clinical studies comparing these two forms. So if you read that one particular pattern is superior to another, you are not reading a verified finding, but a guess with a number in front of it.

This is not an argument against trying it. It is an argument against the precision some instructions suggest. Setting a time window down to the quarter hour implies a level of precision for which there is no data.

Caffeine in figures: the upper limit

Of all the substances covered here, caffeine is the one whose amounts are specified most precisely. The BfR gives three figures that should be read together but are usually cited separately.

Caffeine according to the BfR

Source: German Federal Institute for Risk Assessment (BfR), Questions and Answers on Caffeine and Caffeine-Containing Foods (as of 2026) and Communication 46/2024 on caffeine powder

Why the third figure belongs here

There is a factor of twelve to twenty-five between the second and third figures. That sounds like a wide gap, but it can be bridged quickly with powder, because there is no volume to limit the amount. You can't accidentally multiply a cup of coffee twentyfold, but you can with a spoonful of powder.

The BfR documented the case behind this: a young woman died after accidentally ingesting about 9 grams of highly concentrated caffeine powder, despite intensive medical treatment. Anyone using caffeine as a tool should know this figure, not just the 400 milligrams.

The single dose depends on body weight

The 200 milligrams is not a fixed amount for everyone. The BfR gives it along with its basis: 3 milligrams per kilogram of body weight. That means 200 applies to a person weighing around 67 kilograms.

Someone weighing 55 kilograms comes to around 165 milligrams per single dose using the same calculation, while someone weighing 90 kilograms comes to around 270. This range is wide enough that a blanket cup count misses the mark.

It is also worth noting that the daily amount of 400 milligrams combines all sources. Coffee, tea, cola, energy drinks, and caffeine-containing supplements all count together. People who have a caffeinated sports drink in addition to their coffee often count only one of the two sources.

Cold: what the sources actually say

Cold showers and ice baths are among the most visible biohacking practices. We therefore specifically looked for what medical reference works say about cold exposure.

The result was one-sided. The MSD Manual discusses cold in terms of injury: exposure to cold can cause a drop in body temperature and soft-tissue damage such as chilblains, immersion foot, perniosis, and frostbite. Susceptibility can increase due to factors including exhaustion, malnutrition, and dehydration.

What this does not imply

The fact that a reference work lists cold exposure only under injuries is not evidence against cold showers. It means that the search for an institutional statement about its benefits came up empty in this case.

For everyday life, the main takeaway is about the conditions. According to this source, exhaustion and dehydration increase susceptibility. Taking an ice bath after a hard workout is therefore a different situation from having a cold shower in the morning.

Sleep: the best-studied lever

Sleep is different from the other topics. No one disputes that sleep matters. What is disputed is how much each measure helps.

The Robert Koch Institute has surveyed how common sleep problems are. In an analysis using data from 2024, 16.3 percent of respondents reported difficulty falling asleep and 31.7 percent difficulty staying asleep, with higher rates among women and people with lower levels of education.

Where light therapy is proven to work and where it is not

Light therapy lamps regularly appear on biohacking lists. There is, in fact, a substantiated claim about them, but it is narrowly limited. IQWiG reviewed 21 randomized controlled trials involving a total of 1,441 adults and found evidence of a short-term benefit compared with placebo.

This review concerned the treatment of seasonal affective disorder, which, according to the same source, affects around 2.5 percent of the population each year. Nothing can be inferred from this for healthy people without this diagnosis. According to the same report, no reliable study was found on treating this form of depression with vitamin D.

Dietary supplements and the idea of stacking

A stack is a combination of several supplements intended to enhance one another’s effects. We found no assessment of such combinations in any of the sources we reviewed. What we did find were claims about individual ingredients and the legal framework.

The consumer advice center puts it succinctly: dietary supplements are foods, and they are not intended to alleviate, cure, or prevent diseases. That is what European law says. This makes any advertising claim that links a product to a disease impermissible, regardless of its effects.

What the market makes of this situation

The Verbraucherzentrale Bundesverband points out that so far there have been neither approval procedures nor legally established maximum amounts for vitamins or minerals. That means a product can go on sale without any authority having checked its dosage beforehand.

According to a survey by the same association, 54 percent of respondents had bought at least one food supplement in the past six months, and 95 percent wanted these products to be tested for safety. There is a gap between what people buy and what has been tested.

How to recognize an approved claim

There is one area where advertising claims are actually assessed. Regulation (EU) No. 432/2012 provides a list of approved health claims. What’s on that list may appear on the packaging; what’s missing from it may not.

These approved claims sound deliberately restrained. They say that a nutrient contributes to a normal function. That wording is the tell: contributing to something normal does not mean improving it beyond normal.

Anything beyond that is marketing language. Phrases like speeds up, optimizes, boosts or protects against do not appear on any list of approved claims. Anyone who reads them is reading the manufacturer’s copy, not the findings of an assessment.

Wearables: what you measure and who’s watching

Rings, watches and bracelets are the most visible tools in this scene. We found no assessment of their health benefits from the institutions we checked. We did find assessments of their data practices.

The figure comes from the Verbraucherzentrale, which examined 24 fitness apps. Nineteen of them sent data to varying numbers and types of third parties. The same source reports that 14 percent of German internet users use wearables.

The blind spot in self-tracking

A sensor on the wrist measures movement, heart rate and skin temperature. Software uses these to calculate values such as sleep stages or recovery. The measurement and the displayed value are therefore not the same thing, and the calculation in between is usually not disclosed.

In everyday life, this means that a trend over several weeks is more meaningful than a single daily reading. Comparing Tuesday’s score with Wednesday’s mostly measures fluctuations in the algorithm.

When the number becomes a problem

There comes a point when self-tracking defeats its purpose. Anyone who checks their recovery score first thing in the morning and plans the day around it has got the order backwards: instead of how you feel shaping the score, the score shapes how you feel.

We found no data on how common this pattern is at the institutions we checked, so we make no claims about it. What can be said is how the underlying logic works: an algorithm that translates movement and pulse into a recovery score knows neither about the previous evening nor the week ahead.

One practical way to handle this is to look at the number only in the evening. Then it sits alongside what the day has actually brought, rather than anticipating it. This is not a recommendation from a guideline, but a matter of keeping things in perspective.

What can be measured in your own body

After eight chapters filled with many unanswered questions, the obvious question is: What, then, can be reliably determined? The honest answer distinguishes between two levels.

What a lab measures are concentrations and markers at a given point in time. What a genetic test reads are variants in genetic information that do not change over the course of a lifetime. Both describe conditions; neither provides instructions for action, let alone diagnoses.

Predisposition and condition are two different questions

The difference sounds academic, yet it determines how a result should be read. A genetic variant answers the question of how your body generally responds to something. A blood test answers the question of how you are doing with it today.

The first answer never changes. The second can shift within weeks. Confusing the two levels can lead you to feel pressured to act based on an unchangeable predisposition, or to draw conclusions about your own predisposition from a momentary reading.

For self-tracking, this means: a sensor on your wrist works on a third level, namely that of behavior over time. All three levels together provide a picture, but none replaces the others.

mybody®x works with a certified specialist laboratory in Germany, processes results in compliance with the GDPR, and has been active since 2016, serving end customers since 2022. The following test covers the genetic level.

One note on context is important. Genetic testing for medical purposes in Germany is subject to the Genetic Diagnostics Act, which requires a physician’s involvement and a duty to inform. Anyone seeking to draw a medical decision from a result needs medical supervision.

Limitations: what this article does not answer

Nootropics are deliberately not presented as an option in this article. The MSD Manual describes only the risks of amphetamines and states that at high doses, life-threatening increases in blood pressure and heart rate can occur. It contains no statement about benefits for healthy people without a medical indication.

We found no figures on the prevalence of biohacking, the size of the market or the number of users from any institution. All figures in circulation come from companies or press releases, so they are not included in this text.

None of the sources reviewed address stacks, or combinations of multiple supplements. Neither a warning nor a recommendation can therefore be substantiated, so neither is included here.

One final limitation: this article does not assess whether biohacking is worthwhile. It shows where a verified statement exists for individual practices and where it does not. The decision about what someone tries is their own.

What remains of biohacking

If you take one habit away from this article, let it be this: For every biohacking recommendation, ask for the institution and the year. Not for the study, because studies can be found to support almost any claim, but for the body that summarizes the current state of knowledge.

That question quickly sorts things out. For caffeine, a number from the BfR comes back. For intermittent fasting, a statement from the DGE about a lack of clear evidence comes back. For cold exposure, a chapter on frostbite comes back. Three answers, three different situations.

It began with the question of what possibilities biohacking offers. The most reliable answer is unglamorous: the possibilities lie where a practice has a name, a number and a source. Everything else is an experiment, and an experiment can be called what it is.

Frequently asked questions

Sources

1. German Nutrition Society (DGE): Intermittent fasting. Technical information, status 2018 – dge.de
2. Federal Institute for Risk Assessment (BfR): Questions and answers on caffeine and foods containing caffeine, including energy drinks, status 2026, and Notice 46/2024 on caffeine powder – bfr.bund.de
3. Institute for Quality and Efficiency in Health Care (IQWiG): What can you do about sleep problems? As of 2024 – gesundheitsinformation.de
4. Consumer advice center: Using dietary supplements correctly, as of 2025 – verbraucherzentrale.de

The verbatim quotation on the state of research, the information about the lack of long-term data, and the note that the results come from animal studies are from source [1]. The three caffeine figures and the documented death are from [2]. The statement on sleep hygiene is from [3], and the legal classification of dietary supplements is from [4]. Also cited: the analysis of 21 studies involving 1,441 adults on light therapy and the 2.5 percent figure for seasonal affective disorder from an IQWiG press release (2020); the 16.3 and 31.7 percent figures for difficulty falling asleep and staying asleep from the Robert Koch Institute’s Journal of Health Monitoring (2024 data); information on cold injuries and amphetamines from the MSD Manual (2024 and 2025); the study of 24 fitness apps and the 14 percent usage rate from a study by the consumer advice center; the 54 and 95 percent figures from a survey by the Federation of German Consumer Organisations (2025). Information on price, scope, sample type, and laboratory is from the mybody®x product page, accessed on 11.08.2026. All sources were accessed and reviewed on 11.08.2026.